Find dy/dx by differentiating implicitly and calculate its value with x=5, y=1

(x^2)-(xy^3)=20

This is what I did:

2x-3xy(dy/dx)=0

That answer is wrong. Where am I making the mistakes?

Thank you. Much appreciated.

You made your mistake in the first step, unfortunately. You need to differentiate that as a product rule; you can't just differentiate it as if x were a constant. I'm gonna change things around, so it's a little bit easier. Hopefully this doesn't confuse you...

Differentiating implicitly, you should get
You're trying to isolate , so you can rearrange the equation so it reads as follows: